Internal combustion apparatus



Oct. 20, 1964 J. R.A HAMM INTERNAL coMBus'rIoN APPARATUS Filed Maren 31, i954 :1 .mm m: A

INVENTOR James R.Hamm

ATTORNEY United States Patent O 3,153,323 INTERNAL CMBUSTlN APPARATUS James R. Hamm, Meylan, Pa., assigner, by mesne assignments, to the United States of America as represented by the Secretary ofthe Navy Filed Mar. 31, 1954, Ser. No. 419,999 9 Claims. (Cl. 6ft-39.71)

This invention relates to combustion apparatus, and more particularly to liquid fuel combustion apparatus for a gas power plant or the like.

In operation of combustion apparatus in a gas power plant, it is desirable to effect mixture of the finely divided fuel With air and to rapidly preheat the mixture immediately before combustion thereof, to insure greater combustion etlciency and flame stability.

It is an object of the invention to provide improved combustion apparatus for a gas power plant, or the like, constructed and arranged to effect rapid vaporizing and preheating of the fuel and air mixture.

Another object of the invention is to provide combustion apparatus of the above type constructed and arranged to provide recirculation of a part of the hot products of combustion through the fuel vaporizing means.

A more specific object is to provide combustion apparatus in an annular passage, which apparatus is arranged to provide recirculation of air and part of the hot products of combustion through the fuel vaporizing means.

Theseand other objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawings, forming a part of this application, in which:

FIG. 1 is a diagrammatic View, partly in section, of a gas turbine power plant having combustion apparatus made in accordance with one form of the invention;

FIG. 2 is an enlarged detail, sectional View of a portion of the combustion apparatus shown in FIG. 1;

FIG. 3 is a fragmentary sectional View taken on line III-III of FIG. 2, and indicating the section line lI-ll along which the latter is taken;

FIG. 4 is an enlarged detail, sectional View similar to FIG. 2, but showing another form of the invention and;

FIG. 5 is a fragmentary sectional view taken on line v-v of FIG. 4, and indicating the section une Iv-rv along which the latter is taken.

Referring to the drawings in detail, a typical aviation gas turbine power plant is illustrated diagrammatically in FIG. l, the essential elements of which comprise an outer casing structure 11, which may bemade of a number of cylindrical sections and which has mounted therein an inner core structure 12 cooperating with the outer casing structure 11 to form an annular flow passageway 13 which extends longitudinally through the power plant from an air p intake opening 14 to a discharge nozzle 15. The core structure 12 may include an axially disposed, forwardly directed fairing cone 16 mounted adjacent the intake opening 14 and adapted to house fuel and oil pumps, ignition apparatus, etc., and Va rearwardly directed fairing cone 17 mounted along the longitudinal axis of the casing adjacent the exhaust nozzle 15. It will be understood that the casing structure 11 is adapted to be mounted in or on the fuselage or wing of an air ship, with the inlet opening 14 pointed forwardly.

The operating elements `of the gas turbine plant are arranged in axial alignment and include an axial-flow compressor 1S, combustion apparatus 19 and a turbine 20 which is operably connected to the rotor of the compressor 18 by means of an axially disposed shaft 21.

The operation of the gas turbine plane illustrated in FIG. l is well known and briefly is as follows: Air entering. the annular intake opening 14 flows to the compressor 3,153,323 Patented 0st. Z0, 1964 rice 18, which pressurizes the air and delivers it along the annular passage 13, to the combustion apparatus 19 where it supports combustion of fuel, which may be admitted thereto in a manner which will hereinafter be described. The products of combustion thus generated, together with heated air, form a hot motive fluid which is expanded through the turbine 20 for driving the compressor 18, and is then exhausted to the atmosphere through the nozzle 15, usually in the form of a jet establishing a propulsive thrust.

Referring to FIGS. 2 and 3, in which one embodiment of the invention is shown, the combustion apparatus 19 is of annular form and is disposed in the annular passage 13 between the outlet of the compressor 18 and the inlet of the turbine 26 and comprises a combustion chamber 22 provided by an outer tubular wall 23 and an inner tubular wall 24 disposed in spaced coaxial relation with each other, the outer casing 11 and the inner core structure 12. The outer and inner combustor walls 23 and 24 are connected to each other at their upstream ends (to the left as shown in the figures) by an annular plate 25, hereinafter referred to as the upstream plate. A plurality of axially extending vaporizing tubes or chambers 26 are mounted within the inner and outer combustion walls 24 and 23, preferably in two circular rows and in staggered relation with each other, as best shown in FIG. 3. An annular partition 27 joined to the inner and outer lcombustor walls 24 and 23, respectively, may be provided for supporting the tubular vaporizing chambers 26. The partition 27 is provided with a series of large openings 28 disposed in registry with the vaporizing chambers 26 and is further provided with a plurality of smaller openings 29 which may be arranged in any pattern, for example, in circular rows encompassing the openings 28.

The upstream plate 25 is provided with a plurality of openings 30 for admitting primary air from the passage 13 into the vaporizing chambers 26. Each of the open- .ings 30 is defined by curved surface portions 30a of the upstream plate 25, which curved portions extend into the vaporizing chambers a short distance and are spaced from the walls of the vaporizing chambers by an annular space 30h, thereby forming an air ejector structure.

Fuel may be admitted to the vaporizing chambers 25 by a plurality of fuel nozzles 32 which preferably extend through the openings 39 and which may be connected to a source of fuel supply (not shown) by a common manifold 33 connected to a fuel supply line 34.

It will be noted that the outer and inner combustor walls 23 and 24 form annular air passageways 35 and 36 for flow of diluent air for cooling the casing 11, the core structure 12 and the hot products of combustion prior to admission of the latter to the turbine.

Part of this air may be diverted to the combustion chamber 22 through a plurality of openings 35a, 36a provided in the outer and inner combustor Walls 23 and 24 respectively. It will be noted that the openings 35a and 36a are provided in those portions of the walls 23 and 24 which lie downstream of the vaporizing chambers 26.

The vaporizing chambers 26 are spaced from the outer and inner combustor walls 23 and 24 respectively, thereby forming recirculation passages 37, 38 and 39 connecting the combustion chamber 22 with the upstream end of the vaporizing chambers. It will be noted that in the arrangement shown, the recirculating passages 37, 38 and 39 are in communication with each other.

In operation, with pressurized air from the compressor flowing through the annular passageway 13, primary air is delivered to the vaporizing chambers 26 by means of the openings 30 in the upstream plate. Fuel supplied by the nozzles 32 into the vaporizing chambers 26 is mixed with the primary air passing through the vaporizing chambers and flows downstream through the openings 28 into the combustion chamber. By suitable ignition means (not shown) the fuel mixture is ignited and the resulting hot motive gases fiow downstream to the turbine where they are expanded, creating a resultant rotation ofthe shaft 21 and the rotor of the compressor 18. They are then discharged through the exhaust nozzle 15 in the form of a propulsive jet. Some of the air iiows from the diluent air passages 35 and 36 through the apertures 35a and 36a into the combustion chamber 22 Vwhere it serves to cool the hot motive gases to a temperature which can safely be accommodated by the turbine.

Part of the hot motive gases are drawn through the apertures 29 in the partition 27, through the recirculation passages 37, 33 and 39, through the annular spaces Sfib into the vaporizing chambers by ejector action of the curved surface portions 3fm in the upstream plate. These hot motive gases are at a sufficiently high temperature to promote vaporization of the fuel and air mixture within the vaporizing chambers 26, thereby preparingsuch vaporized mixture for more thorough combustion prior to delivery to the combustion chamber.

The air ejector action is attained in the following manner. As air Hows through the openings into the vaporizing chambers 26, it creates a reduced pressure at the spaces 30h and in the recirculation passages 37, 33 and 39 in communication therewith. Obviously, with a reduced pressure existing in the recirculation passages, the hot motive gases generated in the combustion chamber at a pressure higher than that in the recirculation passages create the fiow described above. recirculating through the recirculation passages 37, 38 and 39 serve additional functions. They heat the walls of the vaporizing chambers 26 prior to admission thereto and further serve to heat the outer and inner combustor walls 23 and 24 to impart some heat to the diluent air passing through the diluent air passages and 36.

Referring to FIGS. 4 and 5, there is shown a second embodiment ofthe invention incorporated in combustion apparatus 119 of annular shape disposed within an annular air passageway 113 formed by outer casing structure 111 and inner core structure 112, in a manner similar to that shown in conjunction with the first embodiment shown in FIGS. 1 through 3, inclusive.

The combustor apparatus 119 is provided by a pair of inner and outer tubular walls 124 and 123, respectively, disposed in coaxial relation with each other and spaced from the outer casing 111 and the inner core 112, thereby providing diluent air passages 135 and 136. The inner and outer walls 124 and 123 define a combustion chamber 122 in the downstream portion somewhat similar to that shown in the first embodiment.

A plurality of tubular walls 541, 51, 52 and 53, disposed in coaxial relation with each other, provide vaporizing chambers 126 and 12651 of annular shape. The vaporizing chamber walls 5d and 53 are mounted in spaced relation with the walls 123 and 124 and together therewith form recirculation passages 137 and 138 of annular shape. An intermediate recirculation passage 139 is defined by the walls 51 and 52. The vaporizing chamber walls may be fastened to the combustor walls 123 and 124 in any desired manner, for example, by partition plates 127a, 127b and 127C which in turn may be joined to each other by struts 54 and 55. The partitions 127a, 127b and 127e are of annular shape and are provided with a series of apertures 129m, 12% and 129C, respectively, which apertures serve to connect the recirculation passages 137, 138 and 139 to the combustion chamber 122.

The upstream ends of the combustor walls 123 and 124 are closed by upstream plate structure including annular plates 125:1, 12511 and 125C spaced from each other and forming annular primary air openings 130 and 130a which are disposed in registry with the annular vaporizing chambers 126 and 126./1, respectively. The air admission openings 130 and 130er are dened by curved portions 56,

The hot motive gases 57, 57 land 58 which extend into the vaporizing chambers 126 and 126g, respectively, for a short distance. As described in connection with the first embodiment, the curved surface 56 and the adjacent curved surface 57 cooperate with eachother to form ejector structure for the vaporizing structure 126, while the curved surface 53 and the adjacent curved surface 57 cooperate with each other to form ejector structure for the vaporizing chamber 126e.

Fuel may be injected into the vaporizingchambers 126 and 126g by means of a series of fuel nozzles 132 connected to a common manifold 133 which in turn is connected to a fuel supply pipe 134. Here again, the fuel nozzles 132 are preferably, though notessentially, extended through the openings 130 and 131m.

The operation of the combustion apparatus 119 is somewhat similar to that of the apparatus 19 previously shown and described. Specifically, as pressurized air is delivered through the annular passageway 113, primary air enters through the openings 130 and 130e into the vaporizing chambers 126 and 126a respectively. Simultaneously therewith, fuel is injected into the vaporizing chambers by means of the fuel nozzles 132, whereupon the 4fuel and air form a mixture which is sent downstream through the vaporizing chambers into the combustion chamber. The fuel and air mixture is ignited in the combustion chamber (by means not shown) and the resultant hot motive gases flow downstream thereof to drive the turbine (shown in FIG. 1). Diluent air flowing through the passageways 135 and 136 is admitted into the combustion chamber through the apertures 135a and 13611, serving to cool the hot motivegases for the same reasons and in the same manner given in connection with the first embodiment.

The primary air W through. the annular. openings and 130a of the air ejector structures formed by the curved surfaces in the upstream plate structure provides a reduced pressure in the recirculation passages 137, 138 and 139, thereby causing some of the hotmotive gases and some of the diluent airto be recirculatedl therethrough in upstream direction and through the vaporizing chambers 126 and 126a, thereby heating the gas and fuel mixture and providing improved fuel vaporization thereof prior to ignition of the fuel and air vapors in the combustion chamber 122.

It will be noted that in this embodiment the recirculating hot motive gasesv also serve to heat the diluent air as it passes downstream over the walls 123 and. 124 and further serves to heat the vaporizingchamber walls 50, 51, 52 and 53 prior to entry into the vaporizing chambers.

It will now be seen that there is provided combustion apparatus for a gas turbine which` promotes vaporization of the fuel and air mixture for more thorough and uniform combustion thereof. Also, it will be noted that the objects of the invention are attained by simple, lightweight structure which is especially adapted for aviation gas turbine power plants requiring light but sturdy and long lived apparatus.

It will further be noted that the invention lends itself to various configurations and arrangements for eiciently and simply providing recirculation of hot motive gases into the vaporizing chambers of combustion apparatus.

It should be pointed out that the partition 27- and the partitions 127a, 127b and 127e shown in the first and second embodiments, respectively, primarily serve to support the vaporizing chambers in the apparatus and may, if desired, be dispensed with provided that other means for supporting the vaporizing chambers is provided.

Whilefthe invention has been shown. in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. Combustion apparatus comprising coaxially spaced casing and core structure for-ming an annular air supply passage, lirst wall structure mounted within said annular passage and providing a combustion chamber, second wall structure disposed within said first wall structure and providing a plurality of fuel vaporizing chambers, said vaporizing chambers being disposed upstream of saidA combustion chamber and in communication therewith, means for admitting fuel to said vaporizing chambers, means including an opening for admitting primary air to each of said vaporizing chambers, said second wall structure further defining, at least partially, a recirculation passage extending from said combustion chamber to said primary air admitting means, said primary air admitting means further including an air ejector structure adjacent at least one said opening, whereby a reduced pressure is adapted to be created in said recirculation passage for drawing hot products of combustion therethrough and into said vaporizing chambers.

2. The structure recited in claim 1 in which said primary air admitting means are provided by an upstream plate connected to said irst wall structure and said air ejector structure comprises a curved surface portion of said upstream plate defining said opening.

3. Combustion apparatus comprising substantially cylindrical casing and core structure forming an annular air supply passage, inner and outer tubular combustor walls mounted in spaced coaxial relation in said passage for providing an annular combustion chamber, upstream plate structure of annular shape connected to said inner and outer combustor walls, said upstream plate structure having a plurality of ejector structures, each of said ejector structures having an aperture adapted to receive a fuel admission nozzle, wall structure disposed within said combustor walls extending in upstream direction toward said upstream plate structure and providing a plurality of axially elongated fuel vaporizing passages, apertured downstream plate structure disposed between said inner and outer combustor walls, said vaporizing passages having communication with the apertures in said ejector structures and at least some of the apertures in said downstream plate, whereby fuel from said nozzles forms a mixture with air admitted to said vaporizing chamber through the apertures in said ejector structures and draws hot products of combustion through the other apertures in said downstream plate by ejector action.

4. The structure recited in claim 3 in which said upstream plate structure is provided with curved surface portions, said curved surface portions encompassing the apertures in said ejector structures and extending toward said vaporizing passages.

5. The structure recited in claim 3 in which said inner and outer combustor walls are disposed in spaced relation with said casing and core structure and define secondary annular air passages therewith for diluent air, said inner and outer combustor walls having a plurality of apertures providing communication between said secondary air passage and said combustion chamber.

6. Combustion apparatus comprising substantially cylindrical casing and core structure forming an annular air supply passage, a first pair of tubular walls mounted in spaced coaxial relation in said supply passage for providing an annular combustion chamber, a second pair of tubular walls mounted in spaced coaxial relation between said first pair of walls and providing an annular fuel vaporizing chamber, means for admitting fuel to said vaporizing chamber, annular upstream plate structure connected to said lirst pair of walls, said upstream plate structure having means including an opening for admitting primary air to said vaporizing chamber, one wall of said second pair of walls cooperating with one wall of said irst pair of walls to provide a recirculation passage, said air admitting means further including air ejector structure for providing a reduced fluid pressure in said recirculation passage, whereby hot products of combustion from said combustion chamber are drawn through said recirculation passage and into said vaporizing chamber.

7. The structure recited in claim 6 in which at least one wall of said first pair of walls is provided with an aperture for admitting diluent air into said combustion chamber, whereby part of the diluent air is entrained with the combustion products drawn through said recirculation passage, and said upstream plate structure has a curved surface portion adjacent said primary air admitting opening, said air ejector structure comprising said curved surface portion.

8. Combustion apparatus comprising substantially cylindrical casing and core structure forming an annular air supply passage, a pair of tubular walls mounted in spaced coaxial relation in said supply passage for providing an annular combustion chamber, a plurality of axially elongated tubular fuel vaporizing chambers disposed between said pair of walls, means for admitting fuel to said vaporizing chambers, an annular upstream plate connected to said pair of walls, said upstream plate having means including an opening for admitting primary air to each of said vaporizing chambers, said pair of walls defining at least in part a plurality of recirculation passages, said air admitting means further including an air ejector structure adjacent each said opening for providing a reduced fluid pressure in said recirculation passages, whereby hot products of combustion from said combustion chamber are drawn through said recirculation passages and into said vaporizing chambers.

9. The structure recited in claim 8 in which at least one wall of said pair of walls is provided with an aperture for admitting diluent air into said combustion chamber, whereby part of the diluent air is entrained with the combustion products drawn through said recirculation passages, and said upstream plate has a curved surface portion encompassing each said primary air admitting opening, each said air ejector structure comprising one said curved surface portion.

References Cited in the le of this patent UNITED STATES PATENTS 

1. COMBUSTION APPARATUS COMPRISING COAXIALLY SPACED CASING AND CORE STRUCTURE FORMING AN ANNULAR AIR SUPPLY PASSAGE, FIRST WALL STRUCTURE MOUNTED WITHIN SAID ANNULAR PASSAGE AND PROVIDING A COMBUSTION CHAMBER, SECOND WALL STRUCTURE DISPOSED WITHIN SAID FIRST WALL STRUCTURE AND PROVIDING A PLURALITY OF FUEL VAPORIZING CHAMBERS, SAID VAPORIZING CHAMBERS BEING DISPOSED UPSTREAM OF SAID COMBUSTION CHAMBER AND IN COMMUNICATION THEREWITH, MEANS FOR ADMITTING FUEL TO SAID VAPORIZING CHAMBERS, MEANS INCLUDING AN OPENING FOR ADMITTING PRIMARY AIR TO EACH OF SAID VAPORIZING CHAMBERS, SAID SECOND WALL STRUCTURE FURTHER DEFINING, AT LEAST PARTIALLY, A RECIRCULATION PASSAGE EXTENDING FROM SAID COMBUSTION CHAMBER TO SAID PRIMARY AIR ADMITTING MEANS, SAID PRIMARY AIR ADMITTING MEANS FURTHER INCLUDING AN AIR EJECTOR STRUCTURE ADJACENT AT LEAST ONE SAID OPENING, WHEREBY A REDUCED PRESSURE IS ADAPTED TO BE CREATED IN SAID RECIRCULATION PASSAGE FOR DRAWING HOT PRODUCTS OF COMBUSTION THERETHROUGH AND INTO SAID VAPORIZING CHAMBERS. 